I've written before that I'm skeptical about the real existence of a meaningful 'self'. From my entry on Memento:

...[consciousness is a] flickering electrical state hallucinating continuity. That is, the space of a synapse is the amount of time in which one is a singular person, and the person who started typing this word is long dead by the time I will have finished writing this sentence.

I don't think there's any non-arbitrary way of deciding what a coherent self is, so I don't think there's a case to be made that the memory wiping procedure in Eternal Sunshine can qualify as any sort of corruption of, or damage to, that self.

What I mean to say by this is that there's no grounds for arguing that the procedure is morally wrong a priori.

That said, I think Eternal Sunshine raises a lot of the reasons that having a concept of self is useful, even if it's arbitrary. And the convenient thing about a utilitarian argument for a concept of selfhood is that the stuff you need it to do provides the answers for where to draw the arbitrary lines.

The characters in Eternal Sunshine make decisions about whether or not to carve out chunks of their personal history in relation to their ability to function as human beings in the contexts they choose. From there, it's a simple matter of quoting Nietzsche -- "What does not kill me makes me stronger" -- to demonstrate the folly of the attempt.

That's glib, though, and there are a lot of situations where an experience could make a person undeniably less strong. PTSD is that by definition. But the spirit of the Nietzsche quote applies, in my opinion, to the cases we see in the film.

Eternal Sunshine and moral goals

Failing to erase their memories would have forced Clementine and Joel to face painful truths about themselves in order to be able to move on from the relationship. I have little doubt that it would have caused both of them to grow as people, but they would have suffered during the process, and might not necessarily be as happy in that future as they are in a future where they repeat the fresh months of their relationship until they die.

In that sense, Eternal Sunshine places at odds the goals of personal happiness, and societal cohesion; individualism and collectivism. By a collectivist moral standpoint, their decisions to wipe their own memory is definitely morally wrong.

But even within the individualist position, they're still failing to explore themselves deeply and fully. Most philosophers argue that that's a form of moral failure.

Eternal Sunshine and medical ethics

I think the procedure featured in Eternal Sunshine has a lot of parallels to other controversial medical procedures. You could argue that it's treated at times metaphorically similarly to abortion and euthanasia, and although obviously neither works as a perfect metaphor in the film, reflecting on those real procedures does ground the argument about the legitimacy of Lacuna's procedure in a less frivolous-sounding debate.

Lacuna does relatively little screening and almost no psychological prep for the procedure. They're fairly indiscreet about how they maintain confidentiality, and they obviously cultivate an atmosphere of low professionalism. (Mierzwiak performs the procedure on Mary after they'd had an affair, Patrick steals a patient's underwear, and all three of the employees drink their patients' booze while operating brain-altering machinery.

I think the best case for a moral issue in this movie is for the incredibly lax regulation on Lacuna's medical practice.